Telescopes generally include optics adapted to focus radiation (e.g., infrared, or IR radiation) onto a detector, such as a focal plane array (FPA). The FPA can be implemented with various known technology, such as charge-coupled devices, quantum well infrared photodetectors, strained superlattice, photovoltaic, photoconductive, or other such imaging devices. The FPA can be cooled, where it is operatively coupled with a Dewar cold finger or other cooling mechanism, but may also be uncooled (such as in the case of a microbolometer). Each cell of the FPA generates a detector current when a scene is imaged from a given field of view (FOV). Each detector current generated by the FPA is applied to the input of a corresponding integrator circuit included in a FPA read-out circuit and digitized or otherwise prepared for subsequent image processing.
In general, such radiation detectors are required to maintain performance in the presence of radiation that is unwanted or otherwise not of interest, including relatively intense radiation sources (solar and others) near the FOV. In such cases, a baffle can be used to prevent the undesired or so-called off-axis radiation from reaching the telescope and detector. In conventional designs, the baffle is cantilevered off, or otherwise appended to, the entrance aperture end of the optical telescope. In some cases, the baffle design may incorporate small cell cube corner retroreflectors to reflect off-axis radiation back out the entrance aperture of the baffle.